// library.cpp
// ----------------------------------------------------------------------
// incomplete; see comments marked that w/ *** 
// misc. library-related functions for use in main.cpp
// 
// CSE 143
// Homework 3
// http://www.cs.washington.edu/education/courses/143/00su/homework/
// 03 Jul 2000
// 12 Jul 2000:  modified to uncomment #include <string.h>


#include <iostream.h>
#include <fstream.h>
#include <iomanip.h>
#include <string.h>
#include <assert.h>

#include "library.h"

const int MAX_LINE_LENGTH = 120;  // when reading from a file

//////////////////////////////////////////////////////////////////////
// misc. utility functions

void waitForChar(void) 
{
  char junkchar;
  cout << endl << "Type a character and ENTER to continue... ";
  cin >> junkchar;
}


//////////////////////////////////////////////////////////////////////
// finances

int computeFine(int daysOverdue)
{
  assert(daysOverdue > 0);
  return (FIXED_FINE + PER_DAY_FINE * daysOverdue);
}


//////////////////////////////////////////////////////////////////////
// I/O

void processTransactionsFile(char fileName[], 
                             LibraryBookList &bookList,
			     LibraryPatronList &patronList)
{
  // Mac and UNIX users:  omit ios::nocreate argument
  assert(strlen(fileName) > 0);
  ifstream inFile(fileName, ios::nocreate);
  if (!inFile) {
    cerr << endl << "unable to open file: " << fileName << endl;
    return;
  }

  // process one transaction per loop iteration
  while (inFile) {
    // dec is not a local variable, but a manipulator that forces cin
    // to read values in decimal (base 10) format
    int month, day, year, userID, bookID;
    char transactionCode; 
    inFile >> dec >> month >> day >> year 
           >> userID >> transactionCode >> bookID;
    Date transactionDate(month, day, year);

    // need to skip the trailing whitespace after bookID,
    // i.e. extract trailing characters, including \n
    char line[MAX_LINE_LENGTH]; 
    inFile.getline(line, MAX_LINE_LENGTH);
                
    if (!transactionIsValid(transactionDate, userID, transactionCode)) {
      cerr << "invalid transaction" << endl;
      return;
    }
    
    processTransaction(bookList, patronList, 
		       transactionDate, userID, transactionCode, bookID);

    waitForChar();		
  } // end loop over lines in file

  inFile.close();
} // end processTransactionsFile


bool transactionIsValid(Date transactionDate, int userID, 
			char transactionCode)
{
    if (!transactionDate.isValid()) {
      cerr << "invalid transaction date" << endl;
      return false;
    }
                
    if (userID <= 0 || 
        !(transactionCode == 'i' || transactionCode == 'o')) {
      cerr << "invalid transaction ID or code" << endl;
      return false;
    }

    return true;
}


// updating this book in bookList entails retrieving a copy of it
// (transactionBook), updating the copy, and replacing the original in
// the list w/ the updated copy

void processTransaction(LibraryBookList &bookList,
			LibraryPatronList &patronList,
			Date transactionDate, int userID, 
			char transactionCode, int bookID)
{
  // find position of book with given ID (bookID) in bookList, then
  // retrieve copy of book object

  // *** your code here


  // find position of patron with given ID (userID) in patronList,
  // then retrieve copy of patron object

  // *** your code here


  // begin printing record of transaction; output date of transaction
  // and whether it is a check-in or -out

  // *** your code here
  


  // depending on transactionCode, call appropriate function (either
  // processCheckOut or processCheckIn) to process transaction and
  // update the book and patron objects retrieved above

  // *** your code here


  
  // update original book object in the list, i.e. replace the object
  // in the list w/ the copy of the object updated by the call to
  // processCheckOut or processCheckIn above

  // *** your code here


  // do the same w/ the patron record

  // *** your code here


  // print out updated book and patron records

  // *** your code here
}


void processCheckOut(LibraryBook &book, LibraryPatron &patron, Date date)
{
  // verify book is not checked out 
  if (book.isCheckedOut()) {
    cerr << "transaction invalid; cannot check out a book "
	 << "which is already checked out" << endl;
    return;
  }

  // verify patron hasn't reached max. number of allowed check-outs
  if (!patron.canCheckOutMore()) {
    cerr << "transaction invalid for patron; " 
	 << "max. number of check-outs reached" << endl;
    return;
  }
      
  book.checkOut(date, patron, LOAN_DURATION);
}


void processCheckIn(LibraryBook &book, LibraryPatron &patron, Date date)
{
  // verify book is checked out
  if (!book.isCheckedOut()) {
    cerr << "transaction invalid; cannot check in a book "
	 << "which is not checked out" << endl;
    return;
  }

  // verify that patron actually has this book checked out
  if (!patron.hasCheckedOut(book.getID())) {
    cerr << "transaction invalid; book not checked out by patron" << endl;
    return;
  }

  if (book.isOverdue(date)) {
    int daysPastDue = book.daysOverdue(date);
                                
    cout << "overdue by " << daysPastDue << " days, ";
    cout << "overdue fine:  " << computeFine(daysPastDue) 
	 << " cents" << endl;
  } // end overdue book

  book.checkIn(patron);
}